The present invention relates generally to the field of lubrication, and more particularly to a reversing feeder used in centralized lubrication systems of the single line type.
Centralized lubrication systems are used in lubrication applications which require predetermined quantities of lubricant to be delivered to a plurality of points of use, such as bearings and the like. Typically such systems employ a positive displacement lubricant pump which supplies lubricant (generally oil or grease) from a lubricant reservoir, to one or more lubricant feeders, from which the lubricant is delivered to the various points of utilization of measured quantities.
Centralized lubrication systems are generally divided into single and dual line types. The present invention relates to a lubricant feeder adapted for use in a single line system. Such systems employ a plurality of feeders connected in series in the main lubricant supply line. The lubrication pump is arranged to pump lubricant through the line first in one direction, until the feeders have all operated in sequence to deliver a measured quantity of lubricant to their respective points of utilization, and then in an opposite direction, by virtue of which the feeders again operate to deliver a measured quantity of lubricant to each of the points of utilization.
The reversing feeder of the present invention is of a type which utilizes a valving piston and a metering piston. The valving piston shifts in response to the biasing force of pressurized lubricant, and in doing so performs a valving function whereby the pressurized lubricant is directed to one end of the metering piston. The metering piston then shifts or moves axially, forcing a measured quantity of lubricant through a feeder outlet to a point of utilization. After the metering piston has shifted completely from one limiting end position to another, the pressurized lubricant is directed through various passages back to the lubricant line in series and thence to the next or subsequent feeder connected in the line.
Reversing feeders of the type generally described are known in the prior art. See, for example, Obergefell et al. U.S. Pat. No. 3,515,245, assigned to the assignee of the present application. Generally, however, such reversing feeders require a pair of check valves in order to operate in the manner described above. The present invention has as a principal object the elimination of one of the check valves, and the advantages which logically derive from such elimination.